This invention relates to films and more particularly to films such as blown films, cast films and the like prepared from linear ethylene polymers and small amounts of acrylonitrile homopolymers or acrylonitrile copolymers.
Linear low and medium density polyethylene copolymers (LLDPE), and linear high density polyethylene are known materials which are widely commercially available. LLDPE is also described in U.S. Pat. No. 4,076,698 which is incorporated herein by reference. A commercially important use of LLDPE is in films which are conventionally prepared by blown film extrusion. Such films have generally good properties but often exhibit undesirably low stiffness for some uses and having marginal MD tear characteristics.
In accordance with U.S. Pat. No. 4,579,912, MD tear can be improved by blending LLDPE with aromatic polymers such as polystyrene or poly(para-methylstyrene). Furthermore, the stiffness of LLDPE is improved without loss of MD tear.
The present invention also relates to improved LLDPE blends and method for preparing improved films, preferably blown films, made therefrom.